This invention relates to the photographic field and, more particularly, to an improved apparatus for changing photographic functions of a camera in accordance with different film characteristics of the film used in the camera.
It is known to adjust automatically photographic functions of a camera in accordance with the characteristics of the film to be used. The following U.S. Patents are exemplary of known arrangements for adjusting such functions: Nos. 3,194,133; 3,422,740; 3,537,374; 3,963,333; 4,000,497; and 4,077,042. These camera apparatus have a chamber for receiving therein film containers having tactile coding structure thereon. The coding structure may take the form of protrusions, ribs, or notches and their size and/or position are representative of some film characteristic, such as film speed. Mechanisms in the chamber engage the coding structure responsive to insertion of the container. Such mechanisms then effect a select photographic function corresponding to the film characteristic. For example, one changes a filter setting. Another positions a stop member to limit shutter blade movement, while still others adjust operation of an exposure control circuit, or vary the output of the photoflash. In U.S. Pat. No. 3,194,133, a film camera is provided with a plurality of switches in a chamber which receives a film container. Each switch is positioned in the path of movement of different abutments provided on correspondingly different containers that are inserted in the chamber. Differently positioned ones of the abutments, representative of different film sensitivities or film speeds, will then actuate a correspondingly different switch for controlling exposure control in accordance with the film speed. There are, however, disadvantages with this arrangement. For instance, it is complicated since for each different film speed there is a requirement for a separate switch. Moreover, with such a complex arrangement, the switching operations are prone to malfunctioning. In U.S. Pat. No. 4,077,042, a single sensing member varies capacitance or resistance of an exposure circuit continously responsive to movement imparted by a coding structure. A drawback of this approach is that slight dimensional errors of the coding structure could mean that the capacitance or resistance values actually achieved are different from those desired.